The present invention relates generally to manually-operated devices for dispensing granular materials beneath the soil and more particularly to a hand-held dispenser which creates a small soil cavity at each location targeted for receiving lawn seed, fertilizer pellets or the like.
A common problem faced by gardeners is getting grass to grow in certain trouble spots in established lawns. Often the source of the problem can be traced to one or more of the following plant growth impediments: inadequate soil nutrients, high soil acidity, compacted soil, soil infected with plant-eating insects or disease organisms, and foreign objects situated just below the ground surface.
Prior art remedies include over-seeding the established lawn, a practice which entails simply throwing by hand or device large amounts of grass seed in places with little or no grass growth. Another approach involves using a tool to scratch the earth where grass is desired and then sowing grass seed across the scratched area.
Hand-held devices for placing the seed directly beneath the surface of the soil include a seed planter recently patented by Mitchell and Mitchell. As disclosed in U.S. Pat. No. 6,279,496, which issued Aug. 28, 2001, the Mitchells"" seed planter comprises an elongated funnel secured to one side of a cane-like member. The technique for using this seed planter is laborious: seed must be dropped manually through the elongated funnel.
Other hand-held prior art devices for spilling seeds on the ground or discharging seeds and/or granulated chemicals below its surface are complicated to construct and to use. A good example of these devices is the seed planter taught by Yeager and Shaner in U.S. Pat. No. 4,165,697. The latter seed planter utilizes a complex mechanism in which jaws open, creating a seed opening in the soil when a slideable soil collar, which normally surrounds the jaws, is retracted. Simultaneously, a scoop recess, carrying a single seed, is brought into alignment with an opening through which the seed can fall downwardly, en route from the hopper to the newly-created seed opening.
Moreover, the cited prior art devices fail to provide for the detection of a basic impediment to lawn maintenance, i.e., sub-soil rocks and the like. If grass is to survive drouth, it must have the freedom to establish its roots to a depth of at least five inches. Unless the gardener can detect and remove any buried foreign object(s) situated less than five inches below the surface prior to sowing or planting grass seed in an affected trouble spot, his attempts to grow grass there will all be in vain.
An object of the present invention is to provide a tool which can be used not only to plant grass seed and dispense granulated chemicals but also, during this planting/dispensing process, to aerate compacted soil and to detect the presence of near surface buried objects, thereby facilitating a gardener""s efforts to overcome a wide range of chemical and physical impediments to the growth of grass in an established lawn.
A further object of the present invention is to provide a hand-held device which, whenever it is used to dispense granular materials below the surface of the ground, also aerates the soil.
A still further object of the present invention is to provide such a hand-held device which dispenses granular materials only when the near surface soil, to a predetermined depth, is free of sizeable rocks and the like.
In accordance with the present invention, there is provided an improved dispenser which includes an elongated shaft, a hopper, and a spring-actuated sleeve to which is affixed a ground-engaging flange. The shaft is rigidly joined to the hopper and defines both a hollow bore and an orifice.
The hollow bore, which begins at an open end of the shaft near its juncture with the hopper, extends longitudinally nearly the entire length of the shaft. Distal from the hopper, the hollow bore terminates in a closed wall. Extending longitudinally from the closed end of the shaft is a soil-piercing spike which is rigidly attached thereto.
The orifice, which is disposed in a sidewall of the shaft proximate with its closed end, fluidly communicates, via the hollow bore, with the hopper. Granular materials stored in the hopper tend to flow out of it, via the bore, and then exit through the orifice whenever the dispenser is held in an upright position and the orifice, normally blocked by the spring-actuated sleeve, is uncovered.
Slideably mounted on the shaft, the spring-actuated sleeve is biased away from the hopper by a helical spring. The ground-engaging flange comprises means for partially overcoming the bias of this spring.
Held between the shaft and a cylindrically shaped collar rigidly attached to the shaft near its juncture with the hopper, the helical spring is compressed between one end of the collar and an annular ring which is affixed to the sleeve. The action of the spring tends to push the annular ring, which extends outwardly from the sleeve and is slideably movable within the collar, against a shoulder disposed within the collar, so as to normally maintain the sleeve in a fully extended position. Moreover, the respective extensions of the shaft and of the sleeve, when the latter is fully extended relative to its coupling with the collar, are such that a portion of the sleeve covers the orifice, blocking it.
In use, granular materials are dropped by gravity out of the orifice whenever the spike can be driven into the soil far enough that the ground-engaging flange is simultaneously thrust against its surface. On the other hand, when the spike encounters a sizeable rock or other buried foreign object, the flange will fail to make contact with the earth, thereby blocking discharge of granular materials from the orifice. The length of the spike determines the depth of the hole created when the spike is driven into the soil, as well as the sub-soil zone in which the improved dispenser can be used to detect buried foreign objects.
Once the dispenser is removed from the soil, the spring-actuated sleeve automatically covers the orifice, thereby preventing seeds and/or granulated chemicals from spilling out while the dispenser is not in service.